bahlorm

Okay guys while I wait for the part to fix the carburetor, another problem that is preventing me from driving the car is the gas gauge. I have done some reading and it seems that most of the time the connections are full of corrosion, and the connection and the sensor for it are both pretty bad. I was wondering if maybe anyone has any ideas on how to clean it. A wire brush would probably work for the connectors, but for the sensor with it being inside the plastic a wire brush would not be able to fit in between that. And also when looking at it, the sensor has 3 spots where it should connect to something. Two going horizontal and one going vertical. And on the prongs themselves there are only 2, one horizontal and one vertical. It doesn't look like one broke off or anything, but it has made me wonder if maybe that is the reason why it isn't working. I was going to just go ahead and get another but these things aren't as cheap as I figured. Most people are saying they are over $100. Also I am having trouble trying to even find one. All the parts stores around here say they don't carry these.

t_g_farrell

iTrader: (1)

You won't find the senders available anymore. They work by resistance, so the dirtier the
connections, the lower the needle goes. Usually you end up with a full tank looking like its
just barely over the half way mark on the gauge or something.

I'm more familiar with the SA version of the sender but one thing I found was that the sender
circuit relies on connectivity to the tank for ground via the sender cover. One thing that can
happen over time is that the sender on one side of the cover is not getting a good connection
thru to the other side where the connection for the sender wires is. On my SA I was able to
fix this by jumping a wire from one of the connections to one of the screws on the cover so
the sender was getting a good signal thru the cover.

The first thing to do is remove the sender and use an ohm meter to make sure the actual
sender is giving the correct resistance on its sweep. If its good then you just need to fix the
connections issues, what ever they are so that the same resistance is seen at the connector.
Theres no easy solution here. You have to work thru it to find out where the extra resistance
is coming from.

If the sender sweep is giving bad resistance values, you may be able to rehab it by taking it
apart. Someone on here has done that before (might have been DivinDriver). Anyway there
were good pics for that on the forum.

DivinDriver

iTrader: (15)

Yeah, was me. I did a writeup on repairing the SA sensor by transplanting an FB resistance element into it; it's in the archive. Pix in there will show you the inside of the sender and how it works.

780rx7

+1 on jumping the ground through the cover. That was exactly our problem and exactly how we fixed it. Works like a champ now.

deadphoenix52

iTrader: (2)

call rotary performance (rx7.com) i was able to order a brand new sender for $80 thru them. of course that was over a year and half ago. idk if they can still get them.

bahlorm

Okay, I will try and reground it since it seems to be the easiest task to do. If that doesn't work I will bust out my multimeter and also check out what Divin has written up. Thanks everyone. My next question related to this is how to get these bolts or whatever it is off that is holding this plate on. From looking through the rear driver side I see 5 or 7 what looks like bolts held in that is very rusted and rounded off, if they aren't supposed to already be round. What fits these things or at least exactly what are they? Or does this just twist off or something? I really have not gotten a very good look at these but it seems like I didn't have a wrench to even turn these.

DivinDriver

iTrader: (15)

Originally, they are philips head screws. Getting a wrench on them would probably be tricky.

bahlorm

Oh wow, well it would explain why they are round lol. I guess they are just so built up with **** the groves for the screw driver was covered up or I was just not looking at it very well. Could be either one

t_g_farrell

iTrader: (1)

They can be notoriously hard to get undone and sometimes require drilling out.
Which implies dropping the tank and makes it an even bigger job. I lived with mine
acting up for several years before I finally dropped the tank to recondition it and
then I did the sender fixup as well. If you can't easily get them out, I would advise
leaving it alone until the time comes to drop the tank.

bahlorm

Ouch. My only problem with that is even after I get it all fixed to where it runs good, my GF won't ride with me in the car until after I get the gas gauge fixed. Mainly because I ran out of gas once already and I have only driven it a few times lol.

t_g_farrell

iTrader: (1)

Just use the mileage method and your trip odometer. When it gets to 200 or 150,
whatever the cutoff makes you feel safe, fill it up. I never ran out of gas when my
gauge was funked up. Grow a pair

bahlorm

Well at that time my car went through 2 gallons of gas within 10 miles lol. So if it continued to do so, it wouldn't last that long.

780rx7

The tank's not that hard to drop. It makes it way easier to work on too. Just follow the steps in the fsm. In regards to the bolts holding the unit on, I found the best way to get them off is to grind off the heads, pull the plate off, soak the remaining studs in bold remover over night and then they should come off fairly easy with vice grips. Thiink safety first though! Drain the tank and flush it with water thouroghly and then let it dry before doing any grinding! While you are letting the studs soak, check the resistance to the sending unit at the different levels according to the fsm with your multimeter and then try using different ground points. It all sounds like a lot of work, but it isn't too bad. The peace of mind of having a gas gauge that works is worth it and it really doesn't cost anything if this is your issue. This was about a two hour project for us. (not including diagnosing the damn ground issue).

bahlorm

Okay that sounds like my next project then and now I have the information to do it, thanks. I had problems with dropping the tank before with gas in it lol. Not fun with a full tank so I will be sure to drain it out before I do anything.

trochoid

iTrader: (6)

Soak the screw heads with PB Blaster or Kroil overnight, then use an impact screw driver on them. Don't have one, go to Sears or Harbor Freight. I always replace the screws with allen head bolts.